Any links associated with the opportunity will be linked to the new project

You will have the option to copy emails, notes, and uploaded files to the project

Custom field values could be copied to the project, provided those fields have been cloned and mapped from opportunities to projects

To convert an opportunity to a project:

Open the opportunity.

Click the Actions menu and select the Convert To Project option.

Enter a name for the new project and select a Won reason, if available.

If you would like to copy the opportunity's uploaded files and links to notes and emails to the new project, click the Copy Emails, Files, and Notes to the New Project checkbox. (Links to files stored on external services, like Google Drive or Dropbox, won't be transferred.)

Click the Convert To Project button.

The new project will open with a confirmation message at the top of the page.